The Baltimore office, which serves half a million veterans in Maryland, is among the nation's worst performers in processing claims, The Baltimore Sun has shown in a series of stories. McDonough's visit was not announced and was not open to reporters.

McDonough met with managers in the office as well as employees who handle the claims processing. They discussed the agency's efforts to transition away from paper claims and toward an electronic system VA officials hope will speed reviews, a senior administration official said.

Weekly data released by the agency show that more than 81 percent of the 16,000 disability claims at Baltimore's office are more than 125 days old. The national average is about 67 percent.

The error rate in Baltimore is the highest in the country at 25.8 percent.